Many current and future medical applications involve or will involve utilization of various types of medical apparatus or devices inside body (in vivo). Such medical apparatus or devices include but are not limited to detection equipments for disease detection, drug carriers for delivering medicines, medical instruments for surgeries, and special devices for integrated treatments. It is often desirable for such medical apparatus or devices to disintegrate, decompose, or be dispelled after their use in vivo.
A common approach so far has been using a single biodegradable or biocompatible polymer (either natural occurring and then modified, or purely synthetic) as the basis for such apparatus or devices. Many of these biodegradable limit the types of original materials that one can use. Metal and inorganic materials are often not used in these apparatus or devices because of their chemical stability. As a result, where desired, inorganic or metal material's mechanical stability or strength has not been utilized.
On the other hand, sometimes, medical apparatus or devices for in vivo medical applications can be as large as several millimeters in size (or several cubic millimeters in volume). It is most desirable for a relatively large apparatus to decompose to the molecular level. However, many materials cannot be disintegrated to molecular level (e.g., a few angstroms in size) in vivo. It is very difficult for all materials used in an advanced, fully functional medical apparatus with optimum performance to completely decompose into the molecular level, even though some materials may be decompose to small molecular level. While some materials disintegrate in certain fluids inside the body when they are used separately, but they cannot be disintegrated when being used as part of a medical apparatus. Further, it is not easy to dispel a medical apparatus even if it is in miniaturized size. Therefore, as the need for microscopic operations and associated miniaturized medical apparatus and devices arise, how to remove or decompose such medical apparatus and devices has become increasingly important and presented a major challenge.
For instance, when detecting and/or curing diseases, under specific circumstances, medical apparatus and devices need to be disintegrated and decompose in vivo in human beings to continue the treatment. Traditional medical therapies use medicine which is expected to provide a relatively long-term, controllable and proportional dose releasing function to treat the diseases. Some therapies use decomposing materials when fabricating a medical device for in vivo treatment. However, there are limited options of materials that are capable of decomposing. Some materials, for example, glasses or ceramics, cannot be used during fabrication due to the fact that they are not decomposable materials.
There are some newly developed therapies aiming at achieving the same purpose. Targeted therapy treats diseases by interfering with specific targeted molecules needed for cancer or tumor growth. Micro-surgical robot is capable of being injected into human bodies and treating diseases at the targeted area.
Detection apparatus may also be needed to be placed into the human body for carrying out various detection tests.
However, both traditional and newly developed detection approaches and therapies face the difficulties in disintegrating after using various types of medical apparatus in vivo, or difficulties in removing the side products of the therapies, i.e., medicine carrier or micro robot, and difficulties in controlling the release of the medicine in a timely manner. Sometimes, it is difficult to remove a medical apparatus such as a miniaturized detection apparatus out of a human body. These drawbacks call for novel decomposing apparatus which not only overcomes existing issues, but also bring enhanced accuracy, safety, and specificity in medical detection, drug release, and surgeries.